Telescopic joint embodying a pressure-actuated packing device

ABSTRACT

A telescopic joint embodying inner and outer telescopic members, a packing device effecting a slidable seal between the members and composed of pliable packing material carried by the outer member and forced against the inner member by fluid pressure acting upon an elastic diaphragm or bladder surrounding the packing material and forcing the latter inwardly over substantially its full length against the inner member, the origin of the fluid pressure force being the interior of the telescopic joint.

United States Patent Hanes et al.

[ Mar. 7, 1972 [54] TELESCOPIC JOINT EMBODYING A PRESSURE-ACTUATEDPACKING DEVICE [72] Inventors: James W. E. Hanes, Ventura; EdwardLan'alde, Santa Barbara, both of Calif.

[73] Assignee: Vetco Oilshore Industries, 111e,, Ventura,

Calif.

[22] Filed: Jan. 16, 1970 [21] Appl, No.: 3,400

[52] U.S. Cl ..285/l06, 61/46, 61/63, 166/5 [51] Int. Cl ..Fl6j 15/46,F16] 17/00 [58] Field of Search ..285/106; 277/34, 34.6, 34.3; 61/46,46.5, 63; 166/5, .6

[56] References Cited UNTTED STATES PATENTS 3,422,505 1/ 1969 Slemrnons..61/46.5 X

3,523,578 8/l970 Nolan et al. ..166/.5

FOREIGN PATENTS OR APPLICATIONS 174,577 10/1965 U.S.S.R. ..277/34.6

Primary Examiner-J. Karl Bell Attorney-Bernard Kriegel [57] ABSTRACT Atelescopic joint embodying inner and outer telescopic members, a packingdevice effecting a slidable seal between the members and composed ofpliable packing material carried by the outer member and forced againstthe inner member by fluid pressure acting upon an elastic diaphragm orbladder surrounding the packing material and forcing the latter inwardlyover substantially its full length against the inner member, the

' origin of the fluid pressure force being the interior of thetelescopic joint.

20 Claims, 5 Drawing Figures PATENTEUHAR 7 I972 3, 647, 245

sum 1 [1F 2 .Zivvewraex.

I JZJMEJW: E. HAWE:

- Ear/020 1:02pm. DE

TELESCOPIC JOINT EMBODYING A PRESSURE- ACTUATED PACKING DEVICE Thepresent invention relates to telescopic joints, and more particularly totubular telescopic joints used in offshore drilling from a floatingvessel.

Telescopic joints are used in offshore drilling from a floating vesselto compensate for the heave of the vessel under wind and wave action. Asan example, the telescopic joint is disposed in a marine riser connectedat its upper portion to the bottom of a floating drilling ship and atits bottom portion to a wellhead fixed to the ocean bottom at themudline, or a telescopic joint may be incorporated in a tubular drillingstring extending from the floating vessel to the drill bit at the bottomof a well bore being drilled.

The telescopic joints heretofore employed have had packing unitsincorporated therein to prevent leakage between the interior andexterior of the marine riser or drill pipe string, or other tubularstring used in performing an operation in the well bore. Some packingunits have utilized the fluid pressure from a suitable source to effecta seal with the inner barrel or member of the telescopic joint. Pressurehas been applied to a diaphragm which acts as the sealing elementbearing against an external surface of the inner tubular member of thetelescopic joint. When wear occurs, replacement of the sealing elementhas involved substantial expense, both in connection with the cost ofthe diaphragm unit itself and the time consumed in effecting thereplacement. In addition, the internal diameter of the packing elementclosely conforms to the outside diameter of the inner barrel or memberof the telescopic joint, because of the necessity for the packingelement to make a relatively close fit against the inner barrel. Whensuch a packing element is to be replaced, a joint in the inner barrelmust be disconnected, and such joint is required to have a decreaseddiameter to permit the packing unit to be moved thereover. In somedesigns of prior telescopic joints, it is necessary for a portion of theinner barrel to be cut off, as by use of a cutting torch, the wornpacking unit removed, a new packing unit installed in its place, and theinner barrel then rewelded. All of the above cases involve considerabletime and expense.

By virtue of the present invention, an initial close fit of the packingagainst the inner barrel is not necessary, since a pressure force isapplied thereto to automatically hold the packing unit alongsubstantially its entire length in slidable sealing engagement with theinner barrel or inner tubular member, thereby permitting its telescopicmovement with respect to the outer barrel or member of the telescopicjoint. A diaphragm surrounds the packing elements, and a force derivedfrom the interior of the telescopic joint is availed of to contract thediaphragm against the packing unit and hold it in firm sealingengagement with the inner barrel. This diaphragm has a much largerinside diameter then the outside diameter of the inner barrel, so thatit is readily passed over comparatively large diameter connections, suchas a standard marine riser pin connector, found in the tubular stringdepending from the floating drilling vessel, The packing element itselfis in such form that it is easily replaced and placed in a positionsurrounding the inner barrel, and without requiring any disconnection ofportions of the inner barrel itself. Accordingly, the packing elementsare readily replaced in a very few minutes, and such elements arecomparatively inexpensive.

In the event that the internal pressure in the tubular string embodyingthe telescopic joint may not exceed the external pressure by too great avalue, the invention contemplates the incorporation of a pressuremultiplier in the telescopic joint, such that the pressure applied tothe diaphragm and the packing unit can be multiplied over the pressureexisting within the telescopic joint. Thus, if the weight of thedrilling mud or other fluid within a marine riser is not deemedto exceedthe weight of the surrounding body of water sufficiently, then thepressure multiplier will increase the pressure applied to the diaphragm,and, consequently, the sealing force of the packing unit against theinner barrel or inner tubular member of the telescopic joint.

A further objective of the invention is to provide a telescopic jointembodying a packing structure that is compressed against the innertubular member in a uniform manner to improve its sealing effectivenessagainst the inner member, and also to minimize its wear.

Another objective of the invention is to relate the compression of thepacking against the opposed sealing surface of the telescopic joint tothe pressure of the fluid medium passing through the telescopic joint,in order to maintain an appropriate relation between the compression ofthe packing structure against the opposed sealing surface of thetelescopic joint to the internal pressure within the telescopic joint,thus exerting increasing or decreasing compression pressures on thepacking unit when the internal pressure within the joint increases ordecreases. Accordingly, the packing unit will have a much longer lifethan the prior devices, since excessive pressures are avoided when theinternal pressure within the telescopic joint is at a lower value.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalforms in which it may be embodied. Such forms are shown in the drawingsaccompanying and forming part of the present specification. These formswill now be described in detail for the purpose of illustrating thegeneral principles of the invention; but it is to be understood thatsuch detailed description is not to be taken in a limiting sense.

Referring to the drawings:

FIG. 1 is a diagrammatic side elevational view of an embodiment of theinvention illustrated in connection with a floating drilling vessel anda well bore underlying the ocean or other body of water in which thedrilling vessel is floating;

FIGS. 2a and 2b together constitute a combined longitudinal section andside elevational view of a telescopic joint and associated parts of amarine riser illustrated in FIG. I, with the inner tubular member orbarrel of the joint fully telescoped within the outer tubular member orbarrel of the joint, FIG. 2!) being a lower continuation of FIG. 2a;

FIG. 3 is an enlarged fragmentary vertical section through the packingunit illustrated in FIG. 2a; and

FIG. 4 is a view similar to FIG. 3 of a modified form of packing unitembodied in the telescopic joint.

As illustrated in FIG. 1, a marine riser A extends between a drillingvessel B floating in an ocean or other body of water C and a locationadjacent to an ocean floor or mudline D from which a well bore E isbeing drilled. A guide base F is secured to the formation underlying theocean floor, in a known manner, and embodies concentric casing hangerstherein (not shown) from which casing strings H depend into the wellbore. For simplicity of illustration, a surface casing H is illustratedas extending downwardly from the guide base F into the well bore, beingheld therein by a suitable surrounding body of cement J. Guide lines Kare attached to the guide base and extend upwardly to the drillingvessel, a guide frame L being secured to a suitable connector M attachedto one of the casing hangers, the frame being adapted to slide along theguide lines. The connector M is attached through suitable couplings Nand a drilling spool P to a blowout preventer R, which, in turn, issecured to a flexible joint S, permitting limited angular movement ofthe marine riser A thereabove with respect to the blowout preventer,this flexible joint being secured by means of a suitable connector T tothe outer tubular member or outer barrel 10 of a telescopic joint W ofany suitable length, which, for example, may be about 20 to 30 feet.

The telescopic joint includes an inner tubular member or inner barrel 1]adapted to move longitudinally within the outer barrel 10 as thedrilling vessel B rises and falls, this inner member being attachedthrough a suitable connector Y to a string of marine riser sections Aextending upwardly to the drilling vessel. At its upper end, the marineriser is secured by a suitable connector X to a nipple Z attached to thebottom of the drilling vessel.

One of the connectors Y is illustrated by way of example in FIG. 211,although it is to be understood that any suitable detachable connectioncan be employed. As shown at the upper portion of FIG. 2a, thedetachable connector includes a box 12 at the lower end of a section ofthe marine riser telescoped over a pin 13 constituting the upper end ofthe inner barrel 1 1, the box having a suitable seal ring 14 sealinglyengaging the pin which has an external peripheral groove 15 receiving asplit, inherently expandable lockring 16 disposed partially within theexternal groove and also partially within an internal groove 17 in thebox member 12. A plurality of radial screws 18 is threaded in the boxand engage the ring 16 to hold it within the external groove for thepurpose of coupling the pin and box members 13, 12 to one another.However,- when the screws 18 are threaded outwardly of the box, anupward strain taken on the marine riser A will cause the upper internaltapered surface 19 on the ring to engage the pin 13 and be expanded fromthe pin groove 15, thereby permitting disconnection of the box from thepin. The assembled connection between the box and pin is made readilywith the screws 18 unthreaded from engagement with the lock ring 16, thebox merely being slipped over the pin with the ring disposed fullywithin the internal groove 17. When the upper end 20 of the pin engagesthe box, the grooves l5, 17, are in alignment, permitting radial inwardthreading of the screws 18 to dispose the lockring l6 partially withinthe pin groove 15.

As the drilling vessel B rises and falls, the telescopic joint W permitsthe marine riser A and inner barrel 11 connected thereto to rise andfall with respect to the outer barrel of the telescopic joint. Toprevent leakage of fluid between the inner and outer barrels, a packingunit 21 is carried by the upper portions of the outer barrel, which isthreadedly attached to the main lower portion of the outer barrel, asdisclosed in FIG. 2a. This packing unit includes a plurality of splitrings 22, or a single spiral or helical ring, made of flexible sealingmaterial, such as braided flax or asbestos, impregnated with alubricant, such as graphite, fluorocarbon (Teflon), or the like, of anoverall extended length and with its inner surface bearing against thecylindrical periphery 23 of the inner tubular member 11, which isdisposed in spaced relation to the inner wall 24 of the outer tubularmember 10 to providean annular space 25 therebetween. The lower end ofthe inner barrel has centering ribs 26 projecting therefrom which extendoutwardly toward the inner wall of the outer barrel, so as to center theinner barrel within the outer barrel. Such centering action is assistedby another set of centering ribs 27 extending from the inner barrel 11toward the inner wall 24 of the outer barrel. The spaces between thecentering ribs provide passages for fluid under pressure within thetelescopic joint to pass into the annular space 25 between the inner andouter barrels.

As disclosed in FIGS. 2a and 3, the lower end of the inner packingstructure 22 rests upon an internal flange 28 of the outer barrel, theexterior of the inner packing structure being spaced radially from theinner wall of the outer barrel to provide an annular space 29therebetween in which a pressure actuated elastomer membrane 30 isdisposed. As shown in FIGS. 20 and 3, this membrane is in the form of atoroidally shaped pliant, elasticbladder or bag surrounding the innerpacking structure 22 and extending from the flange 28 to an upperretainer ring 31 secured to the outer barrel by screws 32, or the like,and extending inwardly to the periphery 23 of the inner barrel andoverlying and bearing against the upper end of the inner packingstructure 22. Fluid under pressure directed to the interior of thetubular bladder 30 will cause the latter to expand inwardly against theinner packing structure 22, forcing the latter along its whole lengthagainst the periphery 23 of the inner tubular member 11, the pressurebeing uniformly applied by the bladder along substantially the entirelength of the inner packing structure 22.

In the form of invention illustrated in FIG. 4, the lower end of theinner packing 22 rests upon a filler or abutment ring 33 supported onthe lower flange or seat 28 of the outer tubular member or barrel 10,the upper retainer member 34, which may be in two halves, being securedto the outer barrel by screws 32, or the like, and extending toward theperiphery 23 of the inner barrel, this upper retainer member having adepending skirt 35 laterally spaced inwardly from the inner wall 24 ofthe outer barrel and bearing against the upper end 22a of the innerpacking structure. The upper retainer member 34 and the lower abutmentring 33 may be made of steel, or other suitable metal.

A membrane 36 of elastomer material, such as rubber, illustrated in FIG.4, is disposed in the annular space 37 between the exterior of the innerpacking 22 and the inner wall 24 of the outer tubular member or barrel,its lower end resting upon the, flange or seat 28 in encompassing andsealed relation against the exterior of the abutment ring 33, with itsupper end surrounding and sealing against the skirt 35 of the upperretainer 34 and also bearing against the upper shoulder 38 of theretainer at the upper end of the skirt. The membrane has an upper lipseal 39 sealingly engaging the inner wall 24 of the outer member 10, andalso a lower lip seal 40 sealingly engaging the inner wall of the outermember or barrel, providing a confined annular space into which fluidunder pressure can be introduced extending along the entire length ofthe elastomer membrane 36 between its upper and lower lip seal portions.Fluid under pressure introduced to the confined space will cause the lipseals 39, 40 to seal against the inner wall 24 of the outer member andalso against the peripheries of the skirt 35 and abutment ring 33 andwill urge the thinner intermediate portion 36a of the membrance to moveinwardly and exert a force on the inner pliable packing structure 22,pressing it against the periphery 23 of the inner barrel uniformly alongits entire length. The inner barrel l I can slide along the packingstructure 22 during its telescopic movement within the outer barrel 10,with assurance that a leakproof seal is provided between the inner andouter barrels.

The fluid pressure introduced into the toroidal membrane 30 of the formof invention illustrated in FIG. 3, or into the chamber 37 of FIG. 4 foraction upon its membrane 36, is derived from the interior of thetelescopic joint W. Such pressure is greater than the pressureexternally of the telescopic joint, since thefluid therein has a muchhigher specific gravity than the sea water surrounding the telescopicjoint. The marine riser A may be full of drilling mud, or other drillingfluid, and this fluid will provide a hydrostatic pressure imposed on theelastic diaphragm 30 or 36 greater than the hydrostatic head of the seawater externally of the telescopic joint W, insuring a differentialpressure or force urging the diaphragm inwardly against the innerpacking unit 22 and insuring continuous pressure or forcing of thepacking unit laterally inwardly against the periphery 23 of the innertubular member or barrel 11. Although the drawings illustrate a pressurebooster arrangement (described hereinbelow) between the interior of thetelescopic joint below the packing structure 21 and the diaphragm 30 or36 for imposing fluid pressure upon the latter, suitable tubularfittings and piping can be employed extending from a point below thelower flange 28 and communicating with the chamber 37, in the form ofinvention illustrated in FIG. 4, or with a fitting 50 passing throughthe upper retainer member 31, of the form of invention illustrated inFIG. 3, which communicates with the interior of the toroidal diaphragm30 and which is in appropriate sealing relation therewith. As shown inFIG. 2, the tubing and fitting connections extend from a point 51 justbelow the lower flange 28, being located within a suitable elongateopening or cavity 52 in the external portion of the outer barrel andrunning to the elastic diaphragm. Actually, however, as illustrated inFIG. 3, a portion of the fluid conductor arrangement just describedconstitutes a pressure booster 53.

The pressure booster is disclosed in both FIGS. 3 and 4. It includes acylinder 54 disposed in the side opening 52 in the outer barrel andhaving a large internal diameter cylindrical portion 55 and a smallerinternal diameter cylindrical portion 56. A large piston 57 is disposedin the large diameter portion and a small piston 58 is disposed in thesmall cylinder portion, there being suitable piston rings 59 thereon forslidable leakproof sealing against the respective cylinder walls. Thehead end 60 of the large diameter cylinder is connected through asuitable fitting 61 with the annular space between the inner and outerbarrels below the lower flange 28, the head end 62 of the small diametercylinder 56 being connected through suitable outlet fittings 63 with thefitting 50 sealed against the elastomer tube of FIG. 3, or in the caseof the FIG. 4 embodiment, the fitting 63 communicates with the annularchamber 37 in which the elastomer membrane 36 is located.

The large and small pistons 57, 58 are interconnected by a piston rod70. The rod end of the large diameter cylinder 55 has a suitable bleedervent or port 71 communicating the interior of the cylinder with the seawater externally of the telescopic joint. The large cylinder 55 andlarge piston 57 constitute a fluid motor; whereas, the small piston 58and small cylinder 56 constitute a fluid pump, the small cylinder 56,its associated fittings 63, and the membrane 30 or chamber 37 beingfilled with a suitable liquid, such as oil. The pressure in thetelescopic joint W passes through the inlet fitting 61 into the largediameter cylinder 55, exerting a force thereon and tending to shift thelarge piston 57 in a direction toward the small cylinder 56 and shiftingthe small piston 58 in the small cylinder 56, the latter developing apressure in the liquid in the small cylinder and the small cylinderfittings and membrane. Such pressure is increased or multiplied by theratio of the cross-sectional area of the large piston 57 to the area ofthe small piston 58. Accordingly, by appropriate selection betweenrelative diameters between the large and small pistons, the unitpressure force available for action upon the diaphragm 30 or 36 may beincreased several times with respect to the unit fluid pressure withinthe telescopic joint W. Accordingly, the uniform force applied againstthe inner packing unit 22 along its entire length is increased severaltimes, insuring against leakage between the interior and exterior of thetelescopic joint through the packing structure 21.

The assembly and disassembly of the packing structure is easilyaccomplished in a minimum of time, and without requiring any structuralchanges to either the inner or outer tubular members 11, 10. This istrue despite the fact that the pin end 13 of the connector Y may be of asomewhat greater diameter than the periphery 23 of the inner telescopicjoint. In disassembling the packing portion of the telescopic joint, itis only necessary to back the screws 18 out to permit the marine riserstand A to be elevated to raise its box 12 off the pin 13, whereupon thescrews 32 fastening the upper retainer member 34 of HG. 4 can beremoved,allowing the retainer member to be elevated completely off theinner tubular member 22, since its inside diameter is slightly greaterthan the maximum outside diameter of the pin 13. The membrance 36 andpacking structure 22 can then be elevated along the inner member 11toward its pin 13, the membrane being elevated along the inner packingelements and removed from the pin since its internal diameter is muchgreater than the diameter of the pin. The inner pliable packing 22 canalso be easily removed, since it is either made of split rings orconstitutes a spiral which is easily unwound partially to provide aninternal diameter greater than the pin diameter.

in the case of the structure illustrated in FIG. 3, the inner packing 22can also be readily removed in essentially the same manner as describedabove in connection with FIG. 4. All that need be done is to disconnectthe outlet fittings 63 from the' fitting member 50 secured to thebladder 30, whereupon the screws 32 securing the upper ring 31 to theouter barrel are removed, such ring and the bladder connected theretothen being elevated out of the outer barrel, with the ring 31 passingover the pin 13 of the connector Y, whereupon the sealing material 22can be removed from the inner barrel very readily, if such material isof the split ring type, or by uncoiling the packing material to a smallextent, if spirally wound.

Replacement of the inner packing structure 22 in both forms of theinvention is also readily accomplished by reversing the above procedure.

If the inner packing structure 22 is of the split ring type, or of thespiral type, it is placed around the outer barrel below the pin 13,whereupon the diaphragm 36 is placed around it, such combination beinglowered into the annular space 37 between the inner and outer barrelsuntil the membrane and filler and abutment ring 33, in the case of theFIG. 4 embodiment, engage the flange 28, whereupon the upper retainer34, which may be made in two parts, is placed into the upper end of theouter barrel and in the location illustrated in FIG. 4, its attachmentto the outer barrel being made by the screws 32.

The same procedure is followed in connection with the form of inventionillustrated in H0. 3.

inasmuch as the diaphragm themselves are only subject to fluid pressureand do not bear against the inner barrel 11, they are not subject towear and have a long effective life. The packing 22 which is subject tothe wear incident to reciprocation of the inner barrel 11 in the outerbarrel 10, is readily replaced, although it has a long effective life inview of the fact that it is uniformly pressed against the periphery 23of the inner barrel over an extended length. Leakage is preventedwithout the necessity for subjecting the membrane 30 or 36 to highpressure differentials to produce a corresponding great compressiveforce applied by the membrane against the inner packing structure 22.Great economies are effected, since seal replacement, when required,need only be made of the inner sealing structure 22 which is ofcomparatively low cost.

We claim:

1. In a joint: first and second members disposed one within the otherand movable with respect to each other; slidable seal means between saidmembers comprising a pliable packing carried by said first member andslidably and sealingly engaging said second member while said membersmove with respect to each other to prevent fluid leakage therebetween, afluid-pressure-responsive pliant, elastic diaphragm carried by saidfirst member and disposed around and engaging said packing alongsubstantially its entire length, said diaphragm being responsive tofluid pressure to apply a uniform force to said packing alongsubstantially its entire length to uniformly force said packing alongsubstantially its entire length against said second member while saidmembers move with respect to each other to prevent fluid leakagetherebetween.

2. ln ajoint as defined in claim 1; said first member being an outermember and said second member being movable within said outer member,said diaphragm encompassing said packing and being urged inwardly byfluid pressure to force said packing laterally inwardly against saidsecond member.

3. In a joint as defined in claim 1; said first and second members beingmovable longitudinally with respect to each other.

4. In a joint as defined in claim 1; said diaphragm being a toroidalbladder bearing against said first member and packing.

5. In a joint as defined in claim 1; said diaphragm having end portionsprovided with lip seals sealingly engaging said first member and anintermediate portion between said end portions bearing against saidpacking.

6. [n a joint as defined in claim 1; said first member being an outermember and said second member being movable within said outer member;said diaphragm being a toroidal bladder encompassing said packing andbearing against said first member and packing, said bladder being urgedinwardly by fluid pressure to force said packing laterally inwardlyagainst said second member.

7. ln ajoint as defined in claim 1; said first member being an outermember and said second member being movable within said outer member;said diaphragm encompassing said packing and having end portionsprovided with lip seals sealingly engaging said first member and anintermediate portion between said end portions urged inwardly by thefluid pressure to force said packing laterally inwardly against saidsecond member.

8. in a telescopic joint: an outer tubular member; an inner tubularmember disposed within said outer member; said members beinglongitudinally movable with respect to each other; slidable seal meansbetween said members comprising a pliable packing slidably and sealinglyengaging the outer surface of said inner member while said members movelongitudinally with respect to each other, a fluid-pressure-responsivepliant, elastic diaphragm carried by said outer member and encompassingsaid packing along its entire length and engaging the exterior of saidpacking to apply a uniform inwardly directed force against said packingalong substantially its entire length to uniformly force said packingalong substantially its entire length inwardly against the outer surfaceof said inner member while said members move longitudinally with respectto each other.

9. In a telescopic joint as defined in claim 8; said diaphragm being abladder bearing against said outer member and packing.

10. In a telescopic joint as defined in claim 8; said diaphragm havingend portions provided with lip seals sealingly engaging said outermember and an intermediate portion between said end portions bearingagainst said packing.

11. In a telescopic joint as defined in claim 8; and means forsubjecting said diaphragm to a fluid pressure force derived from thefluid pressure in the telescopic joint.

12. In a telescopic joint as defined in claim 8; and pressure boostermeans communicating with said diaphragm and interior of the telescopicjoint for subjecting said diaphragm to a unit fluid pressure greaterthan the fluid pressure in the unit telescopic joint.

13. ln a telescopic joint adapted to be incorporated in a tubular stringused in underwater well bore operations and extending downwardly from avessel floating in the water: an outer tubular member; an inner tubularmember disposed within said outer member; at least one of said membershaving a connection for securing said one member to an adjacent portionof the tubular string; said members being longitudinally movable withrespect to each other; slidable seal means between said memberscomprising an elongate pliable packing slidably and sealingly engagingthe outer surface of said inner member while said members movelongitudinally with respect to each other, a fluid-pressure-responsivepliant, elastic elongate diaphragm carried by said outer member andengaging said packing along substantially its entire length to apply auniform inwardly directed force to said packing along substantially itsentire length to uniformly force said packing along substantially itsentire length inwardly against the outer surface of said inner member.

14. ln a telescopic joint as defined in claim 13; and means forsubjecting said diaphragm to a fluid pressure force derived from thefluid pressure in the telescopic joint.

15. In a telescopicjoint as defined in claim 13; and pressure boostermeans communicating with said diaphragm and interior of the telescopicjoint for subjecting said diaphragm to a unit fluid pressure greaterthan the unit fluid pressure in the telescopic joint.

16. In a telescopic joint: an outer tubular member; an inner tubularmember disposed within said outer member and having an upper endconnector of a greater external diameter than the diameter of the outersurface of said inner tubular member; slidable seal means between saidmembers comprising a pliable packing slidably and sealingly engaging theouter surface of said inner member while said members movelongitudinally with respect to each other, a fluid-pressure-responsivepliant, elastic diaphragm carried by said outer member and encompassingsaid packing along its entire length and engaging the exterior of saidpacking to apply a uniform inwardly directed force against said packingalong substantially its en tire length to uniformly force said packingalong substantially its entire length inwardly against the outer surfaceof said inner member while said members move longitudinally with respectto each other, the inside diameter of said diaphragm being greater thanthe external diameter of said connector.

17. In a telescopic joint as defined in claim 16; said diaphragm being abladder bearing against said outer member and acking.

l In a telescopic olnt as defined in claim l6; said diaphragm having endportions provided with lip seals sealingly engaging said outer memberand an intermediate portion between said end portions bearing againstsaid packing.

19. In a telescopic joint as defined in claim 16; means for subjectingsaid diaphragm to a fluid pressure force derived from the fluid pressurein the telescopic joint.

20. In a telescopic joint as defined in claim 16; and pressure boostermeans communicating with said diaphragm and interior of the telescopicjoint for subjecting said diaphragm to a unit fluid pressure greaterthan the unit fluid pressure in the telescopic joint.

ig gg UNIJLED S'lA'lES PATEN'I OFFlCE CER'JQIFICATE OF CORREC'IION3,647,245 ated March 7, 1972 Patent No 1nvcntor(s) JAMES W, E, HANES ETAL It is certified that error appears in the abovc-identificd pfit'eni'and that said Letters Patent are hereby corrected as shown below:

Column 7, line 25, befor e "fluid" (last occurrence) insert --unit--; 7line 25,-cancel "unit" (last occurrence).

Signed and sealed this 5th day of September 1972.

(SEAL) Attest:

ROBERT GOTTSCHALK EDWARD M.FLETCHER JR. Attesting Officer Commissionerof Patents

1. In a joint: first and second members disposed one within the otherand movable with respect to each other; slidable seal means between saidmembers comprising a pliable packing carried by said first member andslidably and sealingly engaging said second member while said membersmove with respect to each other to prevent fluid leakage therebetween, afluid-pressure-responsive pliant, elastic diaphragm carried by saidfirst member and disposed around and engaging said packing alongsubstantially its entire length, said diaphragm being responsive tofluid pressure to apply a uniform force to said packing alongsubstantially its entire length to uniformly force said packing alongsubstantially its entire length against said second member while saidmembers move with respect to each other to prevent fluid leakagetherebetween.
 2. In a joint as defined in claim 1; said first memberbeing an outer member and said second member being movable within saidouter member, said diaphragm encompassing said packing and being urgedinwardly by fluid pressure to force said packing laterally inwardlyagainst said second member.
 3. In a joint as defined in claim 1; saidfirst and second members being movable longitudinally with respect toeach other.
 4. In a joint as defined in claim 1; said diaphragm being atoroidal bladder bearing against said first member and packing.
 5. In ajoint as defined in claim 1; said diaphragm having end portions providedwith lip seals sealingly engaging said first member and an intermediateportion between said end portions bearing against said packing.
 6. In ajoint as defined in claim 1; said first member being an outer member andsaid second member being movable within said outer member; saiddiaphragm being a toroidal bladder encompassing said packing and bearingagainst said first member and packing, said bladder being urged inwardlyby fluid pressure to force said packing laterally inwardly against saidsecond member.
 7. In a joint as defined in claim 1; said first memberbeing an outer member and said second member being movable within saidouter member; said diaphragm encompassing said packing and having endportions provided with lip seals sealingly engaging said first memberand an intermediate portion between said end portions urged inwardly bythe fluid pressure to force said packing laterally inwardly against saidsecond member.
 8. In a telescopic joint: an outer tubular member; aninner tubular member disposed within said outer member; said membersbeing longitudinally movable with respect to each other; slidable sealmeans between said members comprising a pliable packing slidably andsealingly engaging the outer surface of said inner member while saidmembers move longitudinally with respect to each other, afluid-pressure-responsive pliant, elastic diaphragm carried by saidouter member and encompassing said packing along its entire length andengaging the exterior of said packing to apply a uniform inwardlydirected force against said packing along substantially its entirelength to uniformly force said packing along substantially its entirelength inwardly against the outer surface of said inner member whilesaid members move longitudinally with respect to each other.
 9. In atelescopic joint as defined in claim 8; said diaphragm being a bladderbearing against said outer member and packing.
 10. In a telescopic jointas defined in claim 8; said diaphragm having end portions provided withlip seals sealingly engaging said outer membEr and an intermediateportion between said end portions bearing against said packing.
 11. In atelescopic joint as defined in claim 8; and means for subjecting saiddiaphragm to a fluid pressure force derived from the fluid pressure inthe telescopic joint.
 12. In a telescopic joint as defined in claim 8;and pressure booster means communicating with said diaphragm andinterior of the telescopic joint for subjecting said diaphragm to a unitfluid pressure greater than the fluid pressure in the unit telescopicjoint.
 13. In a telescopic joint adapted to be incorporated in a tubularstring used in underwater well bore operations and extending downwardlyfrom a vessel floating in the water: an outer tubular member; an innertubular member disposed within said outer member; at least one of saidmembers having a connection for securing said one member to an adjacentportion of the tubular string; said members being longitudinally movablewith respect to each other; slidable seal means between said memberscomprising an elongate pliable packing slidably and sealingly engagingthe outer surface of said inner member while said members movelongitudinally with respect to each other, a fluid-pressure-responsivepliant, elastic elongate diaphragm carried by said outer member andengaging said packing along substantially its entire length to apply auniform inwardly directed force to said packing along substantially itsentire length to uniformly force said packing along substantially itsentire length inwardly against the outer surface of said inner member.14. In a telescopic joint as defined in claim 13; and means forsubjecting said diaphragm to a fluid pressure force derived from thefluid pressure in the telescopic joint.
 15. In a telescopic joint asdefined in claim 13; and pressure booster means communicating with saiddiaphragm and interior of the telescopic joint for subjecting saiddiaphragm to a unit fluid pressure greater than the unit fluid pressurein the telescopic joint.
 16. In a telescopic joint: an outer tubularmember; an inner tubular member disposed within said outer member andhaving an upper end connector of a greater external diameter than thediameter of the outer surface of said inner tubular member; slidableseal means between said members comprising a pliable packing slidablyand sealingly engaging the outer surface of said inner member while saidmembers move longitudinally with respect to each other, afluid-pressure-responsive pliant, elastic diaphragm carried by saidouter member and encompassing said packing along its entire length andengaging the exterior of said packing to apply a uniform inwardlydirected force against said packing along substantially its entirelength to uniformly force said packing along substantially its entirelength inwardly against the outer surface of said inner member whilesaid members move longitudinally with respect to each other, the insidediameter of said diaphragm being greater than the external diameter ofsaid connector.
 17. In a telescopic joint as defined in claim 16; saiddiaphragm being a bladder bearing against said outer member and packing.18. In a telescopic joint as defined in claim 16; said diaphragm havingend portions provided with lip seals sealingly engaging said outermember and an intermediate portion between said end portions bearingagainst said packing.
 19. In a telescopic joint as defined in claim 16;means for subjecting said diaphragm to a fluid pressure force derivedfrom the fluid pressure in the telescopic joint.
 20. In a telescopicjoint as defined in claim 16; and pressure booster means communicatingwith said diaphragm and interior of the telescopic joint for subjectingsaid diaphragm to a unit fluid pressure greater than the unit fluidpressure in the telescopic joint.